Is An Unwanted Conception Possible Here?

Hi. My boyfriend and I had sex last night. I am on birth control. He wore a condom and came inside me, but after he was pulling his penis out, the condom slipped out. We could not find it in my bed. I went to the bathroom and I found the condom on my lower thigh, close to my vagina. I am wondering if I should be worried or take the contraceptive pill?...